Automatic submersible pump



Nov. 14, 1967 MITSUO INOUE 3,352,246

AUTOMATIC SUBMERSIBLE PUMP Filed Oct. 14, 1965 C v INVENTOR E M/rsuo Ill/00E U dfimfizjfiw 'yflm y .Ezg. L

ATTORNEYS United States Patent ()fifice 3,352,246 Patented Nov. 14, 1967 7 3,352,246 AUTOMATIC SUBMERSIBLE PUMP Mitsuo Inoue, Nishinomiya, Japan, assignor to C.D.M.

Kabushiki Kaisha, Kishiwada, Osaka, Japan, a corporation of Japan Filed Oct. 14, 1965, Ser. No. 495,839 Claims. (Cl. 10325) ABSTRACT OF THE DISCLOSURE A submersible pump having an automatic control device including an upper electrode and an earth which when submerged are electrically connected to close the secondary circuit of a transformer and energize a first relay. The first relay when energized closes a switch in series with a second relay for energizing the same which in turn closes another switch in the pump motor circuit to cause actuation of the pump motor. A third switch directly coupled to the motor circuit switch is closed by the closing of the motor circuit switch to connect the upper electrode with a lower electrode, whereby the secondary circuit of the transformer is maintained closed by way of the lower electrode and earth and the pump continues to operate until the water level drops below the lower electrode.

Disclosure This invention relates to an automatic submersible pump equipped with an automatic operation control device inside the housing. Ordinary small-size pumps direct- 1y coupled with water-tight motors and immersed in water for lifting or discharging of water tend to run idle unless they are tended by an operator, as they continue to operate even in the absence of water due to the drop of the water level. Such idling results not only in a waste of power but in considerably shortened machine life. In order to overcome the defect, the use of a float switch or the like which shuts off the power supply upon the drop of the water level below a predetermined value has been proposed. However, such an accessory increases the pump size correspondingly, and gives great inconvenience to the handling .of portable pumps, though it may not be objectionable for stationary pumps. Furthermore, portable pumps are in most cases used for civil engineering works, and rough handling inevitably causes trouble or damage to float switches which comprise movable parts.

In the light of the foregoing difiiculties, the present invention has for its object provision of a small-size and compact portable underwater pump incorporating an automatic operation control device which is trouble-free in rough handling.

According to the invention, in an automatic submersible pump having an automatic control device to control its operation in response to changes in the water level around it, said pump comprising a pump body, a driving motor casing above the pump body and a sealed compartment for the automatic control device in the top of the motor casing, upper and lower electrodes are provided which are adapted to be electrically connected to an earth of the control device by conduction through water in which the pump is immersed, a transformer being provided the primary of which is adapted to be connected to a power supply and the secondary terminals of which are connected respectively to one input terminal of a rectifier and to the earth, the other input terminal of the rectifier being connected to the upper electrode, a relay coil and a condenser being connected in parallel across the rectifier output and a second relay coil, and a switch closed by energisation of the first relay coil, being connected in series across the transformer primary, the sec- 0nd relay coil, when energised closing a switch in the motor circuit and moving a change-over switch to make a connection between the said lower electrode and the input terminal of the rectifier which is also connected to the upper electrode.

The invention is described hereunder in further detail with reference to the accompanying drawingsin which:

FIG. 1 is a sectional side view of an automatic submersible pump according to the present invention;

FIG. 2 is a connection diagram of a control circuit for automatic operation of the pump in FIG. 1; and

FIGS. 30, 3b and 3c illustrate the relations between the submersible pump according to the invention and different water levels.

Referring to the drawings, the symbol M in FIG. 1 indicates a motor consisting of a casing l, stator 2 and rotor 3, and P indicates a pump comprising a casing 4 and impeller 5. The impeller 5 of the pump P is mounted securely on the rotor shaft 6 of the motor M, and the casings 1 and 4 are directly coupled with each other. On the top of the casing 1, a cover 7 provided with a handle 8 is mounted, and inside said cover 7 an automatic operation control device 9 according to the present invention is incorporated in a water-tight manner. The numeral 10 indicates a shaft seal, 11 cabtyre cord for power supply, and 12 discharge a pipe for the pump. On the upper and lower portions of the casing 1, an upper electrode U and a lower electrode L are arranged, respectively, insulated and slightly exposed from the casing 1. An earth E is for the control device 9 attached to the casing 1, if the casing itself is a good electric conductor. If, on the contrary, the casing 1 is a poor conductor such as a synthetic resin, the earth E is posed from the casing and connected to two additional electrodes protruding from the casing one adjacent each of the upper and lower electrodes U and L. The automatic operation control device 9 has such internal connection as illustrated in FIG. 2. The secondary terminals a and b of the transformer T are connected, respectively, with an input terminal a of a rectifier R and the earth E, while another input terminal b of the rectifier R is connected with the upper electrode U. To the output end of the rectifier R, a relay coil RC is connected, and a condenser C is connected in parallel with the relay coil RC On the primary side of the transformer T, another relay coil RC is connected in series with a normally opened switch S Another normally opened switch S connected by wiring to the feeder of the motor M and a switch S coupled with the switch S are so arranged that they operate as the relay coil RC is energised to close the switch S thereby applying the energizing current to the relay coil RC The terminal b and the lower electrode L are connected by a circuit normally closed by the switch S and the upper electrode U and the lower electrode L are so arranged as to form a closed connection as the switch S works.

When an automatic submersible pump according to the invention comprising the above structure is immersed in water as shown in FIG. 3a, the upper electrode U, the lower electrode L, and the earth E are communicated with one another via water as a conductor, and the secondary circuit of the transformer T is closed, and hence an energizing current runs through the relay coil RC Then, the energized relay coil RC closes the switch S with the result that a sufiicient current is applied to the di-circuit including the relay coil RC and the switch S and that the relay coil RC is energized to close the switch S thereby to actuate the motor M for the pumping operation. At this time, the switch S connects the upper electrode U with the lower electrode L, so that, if the water level drops below the upper electrode U as indicated in FIG. 3b, the secondary circuit of the transformer T will remain closed and the pump P will continue its operation as long as the lower electrode Lis conductively connected to the earth E through the medium of water. If the water level indicated in FIG. 30, the connection between the lower electrode L and the earth E via water will be cut off, and the secondary circuit of the transformer T will be opened, whereby the relay coil RC will be deenergized to open the switch S and the relay coil RC will also be deenergized to open the switch S 'and thus to stop the motor M. As the switch S is coupled at this time with the switch S and returns to the position where it connects thelower electrode -L to the earth E, the operation of the pump will not be resumed unless the water level reaches again the level of the upper electrode U.

As will be understood from the foregoing description, the automatic submersible pump according to the present invention is automatically operated as the water level rises above the upper electrode U, and is automatically stopped as the water level drops below the lower electrode L, and thus the pumping operation is carried outquite positively and entirely automatically without the needof any operator and with no possibility of idling. The automatic operation control device 9 is compactly built inside the top cover 7 of the casing 1. It has many advantages: for example, it can naturally be reduced in size as compared with the conventional float-type devices, and is so rugged in construction that it is trouble-free in rough handling, and always operates positively, even if the pump is not in a vertical position, so long as there is a vertical difference between the positions of the electrodes U and L. The automatic submersible pump of the invention incorporating such an automatic operation control device is extremely suitablefor water lifting and discharging operations in civil engineering and other construction works.

Having thus described my invention, what I claim and desire to secure by Letters Patent of the United States is:

1. In combination, a submersible pump, a motor for driving said pump, and an automatic control device mounted on said pump for controlling the operation of said pump motor in response to changes in the water level around said pump, said automatic control device comprising vertically spaced upper and lower electrodes which when submerged are adapted to be electrically connected to an earth of said control device by conduction through the water in which the pump is immersed, a transformer having a primary circuit which is adapted to be connected to a power supply and a secondary circuit, a rectifier having one input terminal connected to one terminal of said secondary circuit and the other input terminal connected to said upper electrode, the other terminal of said secnected in series with said second relay coil across.

the transformer primary circuit for energizing said second relay coil when said first switch is closed, said second relaycoil, when energized, closing another switch.

in the motor circuit to actuate said pump motor, and a change-over switch means directly coupled to said motor circuit switch operative to make a connection between said lower electrode and the input terminal of said rectifier which is also connected with said uppper electrode in response to the closing of said motor circuit switch, whereby said transformer secondary circuit will remain closed and said pump motor will continue to operate as long as said lower electrode is conductively connected to the earth through the Water in which the pump is emerged.

2. The combination of claim 1 further comprising a condenser connected in parallel with said first relay coil.

3. The combination of claim 1 wherein said pump motor is contained in a casing of good electrical conductivity and the earth of said control device is connected thereto, said upper and lower electrodes being insulated from and protruding outwardly through said casing adjacent the top and bottom thereof, respectively.

4. The combination of claim 1 wherein said pump motor is contained in a casing of poor electrical conductivity and the earth of said control device is connected to two additional electrodes protruding from said casing one adjacent each of said upper and lower electrodes.

5. The combination of claim 1 wherein said pump motor is contained in a casing, and there is a sealed compartment for said automatic control device mounted on top of said casing.

References Cited UNITED STATES PATENTS 2,424,657 7/1947 'Goodrnan 103-25 2,834,845 5/ 1958 Nielsen 103-25 3,019,764 2/1962 Schilling 103-25 3,030,890 4/1962 Galik 103-25 3,118,391 1/1964 Ciabattari 103-25 3,252,420 5/ 1966 Sorensen 103-25 FOREIGN PATENTS 595,750 12/1947 Great Britain.

DONLEY I STOCKING, Primary Examiner.

WILLIAM L. FREEH, Examiner. 

1. IN COMBINATION, A SUBMERSIBLE PUMP, A MOTOR FOR DRIVING SAID PUMP, AND AN AUTOMATIC CONTROL DEVICE MOUNTED ON SAID PUMP FOR CONTROLLING THE OPERATION OF SAID PUMP MOTOR IN RESPONSE TO CHANGES IN THE WATER LEVEL AROUND SAID PUMP, SAID AUTOMATIC CONTROL DEVICE COMPRISING VERTICALLY SPACED UPPER AND LOWER ELECTRODES WHICH WHEN SUBMERGED ARE ADAPTED TO BE ELECTRICALLY CONNECTED TO AN EARTH OF SAID CONTROL DEVICE BY CONDUCTION THROUGH THE WATER IN WHICH THE PUMP IS IMMERSED, A TRANSFORMER HAVING A PRIMARY CIRCUIT WHICH IS ADAPTED TO BE CONNECTED TO A POWER SUPPLY AND A SECONDARY CIRCUIT, A RECTIFIER HAVING ONE INPUT TERMINAL CONNECTED TO ONE TERMINAL OF SAID SECONDARY CIRCUIT AND THE OTHER INPUT TERMINAL CONNECTED TO SAID UPPER ELECTRODE, THE OTHER TERMINAL OF SAID SECONDARY CIRCUIT BEING CONNECTED TO THE EARTH, A FIRST RELAY COIL CONNECTED ACROSS THE OUTPUT TERMINALS OF SAID RECTIFIER, A SECOND RELAY COIL A FIRST SWITCH CLOSED BY ENERGIZATION OF SAID FIRST RELAY COIL, SAID FIRST SWITCH BEING CONNECTED IN SERIES WITH SAID SECOND RELAY COIL ACROSS THE TRANSFORMER PRIMARY CIRCUIT FOR ENERGIZING SAID SECOND RELAY COIL WHEN SAID FIRST SWITCH IS CLOSED, SAID SECOND RELAY COIL, WHEN ENERGIZED, CLOSING ANOTHER SWITCH IN THE MOTOR CIRCUIT TO ACTUATE SAID PUMP MOTOR, AND A CHANGE-OVER SWITCH MEANS DIRECTLY COUPLED TO SAID MOTOR CIRCUIT SWITCH OPERATIVE TO MAKE A CONNECTION BETWEEN SAID LOWER ELECTRODE AND THE INPUT TERMINAL OF SAID RECTIFIER WHICH IS ALSO CONNECTED WITH SAID UPPER ELECTRODE IN RESPONSE TO THE CLOSING OF SAID MOTOR CIRCUIT SWITCH, WHEREBY SAID TRANSFORMER SECONDARY CIRCUIT WILL REMAIN CLOSED AND SAID PUMP MOTOR WILL CONTINUE TO OPERATE AS LONG AS SAID LOWER ELECTRODE IS CONDUCTIVELY CONNECTED TO THE EARTH THROUGH THE WATER IN WHICH THE PUMP IS EMERGED. 